Blackboard-rubber



(No Model.)

J. DOONER'.

BLAGKBOARD RUBBER.

Patentedl Aug. 28, 1883.

PATENT yEEICE..

JOHN DOONER, OF SAN FRANCISCO, CALIFORNIA.

BLAeKBoARD-RUBBER.

SPECIFICATION forming part of Letters Patent No. 283,870, dated August 28, 1883.

Application filed January 20, 1883. (No model.) V

To all whom, it may concern:

Be it known that I, JOHN DooNEE, of San Francisco, State of California, have invented an Improved Blackboard-Rubber; and I hereby declare the following to be a full, clear, and exact description thereof. y.

My invention relates to certain improve ments in rubbers or erasers to be used upon blackboards; and it consists in certain details of construction and arrangement of parts, as hereinafter fully described and claimed.

Referring to the accompanying drawings for a more complete explanation of my invention, Figures l and 2 are perspective views of my eraser. Fig. 3 shows the parts in perspective separated, and Fig. 4L is a section showing the manner of fastening.

A is the main body of the device, which, in

the present case, consists of an elongated diamondshaped hollow case, which is of sufficient depth to serve as a convenient handle; and it has a fiat portion or flange, B, projecting from its lower open edge,as a protection from dust. A second frame or body, C, is formed like the part A, and small enough to slide snugly within the part A. rIhis body C serves as a support forthe erasing material, which may consist of felt or narrowstrips of cloth or listing I) wound around it in the direction of its length until a sufficient thick` ness has been obtained, and the material then stands with its edge presented as the` rubbingsurface, the rear edge bearing against flange B when C is placed in I3, and the front projecting beyond the body C. When the erasing material and body C are first put together, the erasing material, being new, will cover most of the body C, which will only enter the body A a short distance at the back, where it is uncovered, but as the erasing material becomes worn the body C is pushed farther into the part A and a fresh amount of the erasing-surface is from time to time exposed until it is worn out, when new material may be supplied. A series of holes, F F, are placed in line, so that the holes Fl in the inner body, C, will coincide with the holes F in the body A as the former part is pressed farther into the latter. In the present case I have shown the body parts A C as united by the spring-clamps E; but it will. be manifest that other fastening devices may be employed without essentially altering my invention.

, I-Iaving thus described my invention, what I claim as new, and desire to secure by Letters Patent, isu 1. In a blackboard-eraser, the hollow body A, in combination with the body C, around the outside of which erasing material is wound, said body being fitted to slide within the part A, as set forth.

2. The hollow bodies A and C, provided with perforations, the body C, carrying erasing material D, said body being adjustable within the body A, in combination with the holding device E, as set forth.

3. In a blackboard-eraser, a main frame or `body, and a secondary frame fitted within the main portion, and adapted to receive the erasing material around its periphery and below the main portion, in combination with locking devices by which the two frames may be secured together, substantially as herein described.

In witness whereof I have hereunto set my hand.

JOHN DOONER. Vitnesses:

G. W. EMERSON, i

S. H. NoUEsE. 

